In a video message seen by the Observer, Asia Bibi’s husband, Ashiq Masih called on the British prime minister to “help us exit from Pakistan” where thousands of people have protested against the supreme court’s ruling and demanded that she be punished.

The plea came a day after Imran Khan’s government announced it would try to prevent Bibi from leaving the country, which her supporters likened to “signing her death warrant”.

Asia Bibi has been on death row in Pakistan. Photograph: AFP/Getty Images

Bibi, a farm labourer, spent eight years on death row after being falsely accused of insulting the prophet Muhammad. This followed a row after she had sipped water from the same cup as a Muslim. On Saturday her lawyer, Saif-ul-Malook, said he had fled Pakistan in fear of his life.

In the message recorded on Saturday, Masih, 55, called on May, as well as the prime minister of Canada, Justin Trudeau, and US president Donald Trump, to bring his family and their longstanding guardian, Joseph Nadeem, to safety in the west.

“I am requesting the prime minister of Britain to help us exit Pakistan and give us asylum if she can,” he said, speaking slowly in a bare white room in a safe house in Pakistan. “We are so under threat we are stuck in this house,” he said later on WhatsApp, requesting that the media refrain from sharing the video to keep his identity hidden.

Wilson Chowdhry, of the British Pakistani Christian Association, said Masih had already applied for asylum at one western embassy but it was not expediting the request. Chowdhry said the family needed “immediate asylum”, adding that it was “incredible” no government had stepped forward so far. “It would not do for her to die because of the tangle of red tape,” he said. The association has launched a petition calling on Jeremy Hunt, the British foreign secretary, to grant Bibi’s family asylum.

The overturning of Bibi’s death sentence infuriated Islamists and on Thursday a petition was filed calling on the supreme court to reverse its verdict. The government of Khan’s Pakistan Tehreek-e-Insaf agreed not to oppose the petition in a much-criticised pact signed with protest leaders on Friday night, in which it also said it would seek to place Bibi, 47, on the Exit Control List (ECL), which would bar any flight.

In return, Tehreek-e-Labbaik Pakistan (TLP), a fast-growing political party dedicated solely to punishing blasphemy, ended its protest, leaving behind charred husks of burnt-out vehicles on the motorways it had blockaded.

On Saturday Rowan Williams, the former archbishop of Canterbury, said the refusal of the Pakistani authorities to allow Bibi to leave the county was a tragedy.

“The Pakistani government has to decide whether it respects the rule of law or not. Asia Bibi has at last been cleared in court of a fabricated charge. The delay in securing justice for her has already damaged respect for Pakistan worldwide,” he told the Observer.

“This latest development is another tragedy not only for Asia Bibi but for a nation whose foundational principles honoured religious freedom.”

A senior Conservative MP urged the Foreign Office to raise Bibi’s case with the Pakistani government. Tom Tugendhat, the chair of the foreign affairs select committee, said: “I will be asking the Foreign Office for an urgent evaluation of the situation and assurance from the Pakistan government that Asia Bibi, who has been found innocent by the supreme court, will not be abandoned to a hate-filled mob.

“It is clear that Ms Bibi, and other religious minorities, are in grave danger and prime minister Imran Khan needs to decide if he believes in the rule of law or the rule of the mob.”

Pakistan’s 3 million Christians are lying low in the aftermath of the court ruling. The government ordered them not to attend the graves of family members on All Soul’s Day, which fell on Friday, saying that large gatherings could present a target for attack.

One senior community member told the Observer he had temporarily removed the cross from his car’s rear view mirror. “It’s very difficult to stay in this country now,” added a Christian woman. “I feel scared.”